Selection of superhard grinding tools

 

① Resin binder (code B)

 

It uses thermoplastic phenolic resin as the main bonding material, and some use epoxy resin and polyimide resin as the main materials, and add a certain amount of fillers, such as chromium oxide, iron oxide, zinc oxide, copper powder, graphite, corundum abrasive, silicon carbide abrasive, etc. After fully mixing with superhard abrasive at a certain concentration, it is heated in the mold and formed under pressure. In superhard abrasive tools, the proportion of resin binders used is about half.

 

Resin bond has a weak bonding strength to abrasives, resulting in good self sharpening during grinding, less clogging, high grinding efficiency, low grinding force, low grinding temperature, and a certain degree of elasticity of the bond itself, which has a certain polishing effect and good surface quality. Therefore, resin bond superhard abrasive tools have a wide range of applications. Mainly used in situations where high grinding efficiency and low surface roughness are required. Its disadvantage is poor wear resistance, high wear of grinding tools, and unsuitable for heavy-duty grinding. Resin diamond grinding wheels are commonly used for semi precision and precision grinding of hard alloys and non-metallic materials. Resin cubic Boron nitride abrasive tools are mainly used for semi precision grinding and fine grinding of high vanadium high-speed steel, Tool steel, stainless steel, heat-resistant alloy and other materials.

 

② Ceramic binder (code V)

 

Ceramic bonded superhard abrasive tools have better wear resistance and bonding ability than resin bonded superhard abrasive tools. They have sharp cutting edges, high grinding efficiency, low heat generation and blockage during the grinding process, and low thermal expansion. They are easy to control machining accuracy and easy to repair. Generally used for rough grinding, semi precision grinding, and forming grinding with large contact surfaces. Its drawbacks are the high surface roughness value of the grinding surface, making it difficult to manufacture, and the increasing application of ceramic bonded CBN grinding wheels in ball screws, guide rails, gears, bearings, crankshafts, camshafts, and titanium alloy grinding.

 

③ Metal binder (code M)

 

Including binders such as bronze and cast iron.

 

Bronze binder has high strength, good wear resistance, less wear, long service life of grinding tools, good shape retention, low grinding cost, and can withstand large loads. However, its self sharpening property is poor, and it is easy to block and heat, making it difficult to repair. Bronze bonded diamond grinding tools are mainly used for coarse and fine grinding of non-metallic hard and brittle materials such as glass, ceramics, stone, concrete, semiconductor materials, and various processes. Bronze bonded cubic Boron nitride abrasive tools are mostly used for honing and grinding alloy steel workpiece materials, and the effect is remarkable.

 

To improve the self sharpening of bronze bonded superhard abrasive tools, some use the addition of tin content to reduce the copper content; Some add a certain amount of ceramics to the bronze bond and sinter it together to increase the brittleness of the bond, which also becomes a metal ceramic bond. Add a certain amount of conductive materials such as silver powder to the bronze binder, specifically used for electrolytic grinding. In addition to silver, some bronze binders also include chemical compounds such as polytetrafluoroethylene,